Ross can make this work, but your geometry requirement is obviously a bit different. Don't think the bearing load would be a problem for the original dwg
I just based mine on ease of construction and cheap Ali box. Trying to keep it simple to build is also worth concidering. I also based the bearing strength from this thread I posted earlier in the year
http://www.mycncuk.com/forums/showth...supported-rail

Dont forget that I was aiming to get the most out of the rails and therefore designing for the smallest possible size, again to save cost and weight. But if your 2 rails and blocks can still handle the load at 25% capacity then its not worth worrying about and save your y travel


It dose look a bit narrow to me tho. dont forget that making it wider will reduce the torque arm caused by the long z axis. (fun this design stuff eh....)